The Internet has become a popular advertising medium. When users browse the world-wide-web, for instance, banner and other ads are a mainstay of many different web sites. Some of these web sites, usually the larger ones, handle their own placement of ads on their pages. However, many other web sites allow a third party to determine which ads should adorn their sites, in exchange for credits to display their own ads on others' web sites.
This is typically accomplished as follows. When a user visits a page of a web site, the web site returns a web document which contains instructions to the web client to obtain and display an ad from a third part server. The third party server attempts to match predetermined characteristics of the web site, and also potentially characteristics of the user visiting the site, with similar predetermined characteristics of an ad of an advertiser. The server then instructs the web client where to find the ad. For example, the server may pass on a link to the web site that the site can return to the user's browser, where the link is to an image for the ad that the server has determined should be displayed on the site.
This process provides for targeted advertising. A web site about sports, for example, may prefer advertising about sports. Thus, ads that have characteristics indicating sports will desirably be matched for display on the web site. Targeted advertising allows for a premium to be charged to advertisers over untargeted advertising, because presumably the users viewing the ad are a priori more interested in the subject matter being advertised. For example, a user visiting a sports-oriented web site is more likely to be receptive to sports-oriented ads, as opposed to a user visiting a bridal-oriented web site.
A difficulty with targeted advertising on web sites is that the third parties responsible for serving the ads to various web sites must constantly manage a large amount of inventory. That is, the third parties typically have a large number of web sites with various characteristics that require matching to a large number of banner ads with various characteristics. Salespeople for the third parties must be able to know at a given time the types of web sites that have space available for showing ads, so that they can sell this available inventory to advertisers desiring to advertise on these types of web sites. Inventory management also becomes more difficult for cooperative-based advertising. That is, some third parties, besides selling space on web sites to advertisers, also allow the operators of these web sites to show their own ads on others' web sites. For these and other reasons, therefore, there is a need for the present invention.